It was built by the European Organization for Nuclear Research (CERN) from 1998 to 2008, with the aim of allowing physicists to test the predictions of different theories of particle physics and high-energy physics, and particularly for the existence of the hypothesized Higgs boson and of the large family of new particles predicted by supersymmetry. The LHC is expected to address some of the most fundamental questions of physics, advancing the understanding of the deepest laws of nature. It contains six detectors each designed for specific kinds of exploration.

The LHC lies in a tunnel 27 kilometres (17 mi) in circumference, as deep as 175 metres (574 ft) beneath the Franco-Swiss border near Geneva, Switzerland. Its synchrotron is designed to collide opposing particle beams of either protons at up to 7 teraelectronvolts (7 TeV or 1.12 microjoules) per nucleon, or lead nuclei at an energy of 574 TeV (92.0) per nucleus (2.76 TeV per nucleon-pair). It was built in collaboration with over 10,000 scientists and engineers from over 100 countries, as well as hundreds of universities and laboratories.

On 10 September 2008, the proton beams were successfully circulated in the main ring of the LHC for the first time, but 9 days later operations were halted due to a magnet quench incident resulting from an electrical fault. The following helium gas explosion damaged over 50 superconducting magnets and their mountings, and contaminated the vacuum pipe. On 20 November 2009 they were successfully circulated again, with the first recorded proton–proton collisions occurring 3 days later at the injection energy of 450 GeV per beam. On 30 March 2010, the first collisions took place between two 3.5 TeV beams, setting the current world record for the highest-energy man-made particle collisions, and the LHC began its planned research program.

The LHC will operate at 4 TeV per beam until the end of 2012, 0.5 TeV higher than 2010 and 2011. It will then go into shutdown for 20 months for upgrades to allow full energy operation (7 TeV per beam), with reopening planned for late 2014.

With a budget of 7.5 billion euros (approx. $9bn or £6.19bn as of Jun 2010), the LHC is one of the most expensive scientific instruments ever built. The total cost of the project is expected to be of the order of 4.6bn Swiss francs (approx. $4.4bn, €3.1bn, or £2.8bn as of Jan 2010) for the accelerator and SFr 1.16bn (approx. $1.1bn, €0.8bn, or £0.7bn as of Jan 2010) for the CERN contribution to the experiments.

The construction of LHC was approved in 1995 with a budget of SFr 2.6bn, with another SFr 210M towards the experiments. However, cost overruns, estimated in a major review in 2001 at around SFr 480M for the accelerator, and SFr 50M for the experiments, along with a reduction in CERN's budget, pushed the completion date from 2005 to April 2007. The superconducting magnets were responsible for SFr 180M of the cost increase. There were also further costs and delays due to engineering difficulties encountered while building the underground cavern for the Compact Muon Solenoid, and also due to faulty parts provided by Fermilab. Due to lower electricity costs during the summer, it is expected that the LHC will normally not operate over the winter months, although an exception was made to make up for the 2008 start-up delays over the 2009/10 winter.

The Large Hadron Collider gained a considerable amount of attention from outside the scientific community and its progress is followed by most popular science media. The LHC has also sparked the imaginations of authors of works of fiction, such as novels, TV series, and video games, although descriptions of what it is, how it works, and projected outcomes of the experiments are often only vaguely accurate, occasionally causing concern among the general public.

The novel Angels & Demons, by Dan Brown, involves antimatter created at the LHC to be used in a weapon against the Vatican. In response CERN published a "Fact or Fiction?" page discussing the accuracy of the book's portrayal of the LHC, CERN, and particle physics in general. The movie version of the book has footage filmed on-site at one of the experiments at the LHC; the director, Ron Howard, met with CERN experts in an effort to make the science in the story more accurate.

The novel FlashForward, by Robert J. Sawyer, involves the search for the Higgs boson at the LHC. CERN published a "Science and Fiction" page interviewing Sawyer and physicists about the book and the TV series based on it.

CERN employee Katherine McAlpine's "Large Hadron Rap" surpassed 7 million YouTube views. The band Les Horribles Cernettes was founded by female members of CERN. The name was chosen so to have the same initials as the LHC.

National Geographic's "World's Toughest Fixes," Season 2 (2010) Episode 6 "Atom Smasher" features the replacement of the last superconducting magnet section in the repair of the supercollider after the 2008 quench incident. The episode includes actual footage from the repair facility to the inside of the supercollider, and explanations of the function, engineering, and purpose of the LHC.